Just before the fire department sprayed the water they measured a level of about 3,400+ Micro Sieverts at reactor #2, which has been almost completely destroyed.

After the spraying, the level was 3,900+.

In other words, there was only a negligible change in the radiation level, which is still dangerous at the plant.

So unless another technique is found, the level will possibly hover indefinitely around a figure that can cause serious health problems in that vicinity. That means people working at the nearby still-functioning reactors may be exposed to serious levels of radiation. Realistically, there probably could be no power generating operation there.

The good news is that, like light (a form of radiation), radiation levels decrease exponentially the further one gets from the source.

This means that people in Tokyo are fairly safe for now. As for the US receiving exposure, I would say it is hardly a concern at this point.

I watch for at least an hour a day and have not heard any experts suggest a different method for reducing the radiation level.